This is a required assignment worth 20 points (20-points/1000-points). Assignment must be submitted by the due date. No late assignments are allowed. Please discuss the following topics and provide substantive comments to at least two other posts.
Select from the following list four (4) topics and discuss. Use only 50-words max per topic to discuss and present your answer. The discussion questions this week are from Chapter’s 3 & 4 (Jamsa, 2013).
Chapter 3 topics:
- Define and describe PaaS.
- List the benefits of PaaS solutions.
- Describe potential disadvantages of PaaS.
- Describe how a cloud-based database management system differs from an on-site database.
- List the computing resources normally provided with a PaaS.
Chapter 4 topics:
- Define and describe IaaS.
- Define and describe system redundancy. Discuss how you might use IaaS to implement a redundancy plan.
- Define and describe load balancing. Discuss how you might use IaaS to implement load balancing.
- Define and describe NAS. Assume you must implement a shared file system within the cloud. What company would you select? Why? What costs should your client expect to pay for cloud-based data on a gigabyte (GB) basis?
- Define and describe colocation. Discuss how you might use IaaS to implement colocation.
- Compare and contrast a cloud-based disk storage device (with a file system) with a cloud based database.
- Compare and contrast physical, dedicated virtual, and shared virtual servers. Search the web for companies that provide each. What cost should a customer expect to pay for each?
NOTE: You are required to use at least two-peer reviewed sources (besides your textbook) to answer the above questions.
School of Computer & Information Sciences
ITS-532 Cloud Computing
Chapter 3 – Platform as a Service (PaaS)
• Define and describe the PaaS model.
• Describe the advantages and disadvantages of PaaS
• List and describe several real-world PaaS solutions.
• List and describe cloud-based database solutions
and describe their advantages.
• Discuss the development history that led to PaaS.
Platform as a Service (PaaS) Defined
Provide a collection of hardware and software resources that developers can use to
build and deploy applications within the cloud.
Depending on their needs, developers may use a Windows-based PaaS solution or
a Linux-based PaaS.
• Developers eliminate the need to buy and maintain hardware, and
the need to install and manage operating system and database
• Because the computing resources no longer reside in the data
center, but rather in the cloud, the resources can scale on demand
and the company can pay for only resources it consumes.
• Further, because PaaS eliminates the developers’ need to worry
about servers, they can more quickly deploy their web-based
• Some developers and administrators want
finer control over the underlying systems
(versions, patch releases/applications, …)
Real World: Google App Engine
• Google App Engine, sometimes called GAE, is a PaaS solution
that lets developers create and host web-based applications
that reside and run on services managed by Google.
• Like many Google services and offerings, Google App Engine
is a free service.
• Google App Engine provides platform support for a variety
of programming languages, the three most common of
which are Java, Python, and Go.
Google App Engine Continued
• Google App Engine features include the following:
Support for dynamic web pages
Data storage and query support
Load balancing for application scalability
Application program interface (API) support for application-based e-mail through Google services
A local development environment that simulates Google App Engine on the developer’s computer
Support for event scheduling and triggering
An application sandbox that limits access to the underlying operating system
An administrative console for managing applications
Real World: Taleo Human-Resources SaaS
• To achieve wide-scale use, an SaaS solution must
have large market potential.
• Every business must recruit, hire, train, and
• The Taleo cloud-based talent management system
provides applications and services to meet
company human resources demands.
Google App Engine
Evolution to the Cloud
Internet Service Providers (ISPs)
• Large capital investment for data-center-based computers
• Large, expensive disk and tape storage systems that often
provided only limited storage capacity
• User interface to the system provided through dumb
• Limited computer–network interconnectivity
• System security maintained through physical security (few
users had direct access to the computer hardware)
Large physical footprint
Considerable heat generation and power consumption
Internet Service Providers (ISPs)
• Reduced cost: The ISP provided the high-speed, highbandwidth Internet connection, which it shared across
• Less server administration: The ISP managed the servers to
which developers uploaded their solutions.
• Less hardware to purchase and maintain: The ISP
purchased and managed the hardware and managed the
infrastructure software, such as the operating system.
ISP Advantages Continued
• Greater system uptime: Through the use of
redundant hardware resources, the ISP
provided high system uptime.
• Potential scalability: The ISP had the ability to
move a high-demand application to a faster
Reduced server footprint
Reduced power consumption and heat generation
Real World: Force.com PaaS
To extend its cloud capabilities to application developers, Salesforce.com has released the
Originally developed to provide a home for business applications, Force.com now runs applications
across most sectors.
Benefits of PaaS
• By shifting computing resources from an on-site data
center to the cloud, PaaS solutions offer:
– Lower total cost of ownership: Companies no longer need
to purchase and maintain expensive hardware for servers,
power, and data storage.
– Lower administration overhead: Companies shift the
burden of system software administration from in-house
administration to employees of the cloud provider.
Benefits of PaaS Continued
– More current system software: The cloud administrator is
responsible for maintaining software versions and patch
– Increased business and IT alignment: Company IT personnel can
focus on solutions as opposed to server-related issues.
– Scalable solutions: Cloud-based solutions can scale up or down
automatically based on application resource demands.
Companies pay only for the resources they consume.
Disadvantages of PaaS
• Potential disadvantages of PaaS solutions include:
– Concerns about data security: Some companies are hesitant to move
their data storage off-site.
– Challenges to integrating cloud solutions with legacy software: A
company may need to support on-site solutions as well as cloud-based
solutions. Communication between the two application types may be
difficult to impossible.
– Risk of breach by the PaaS provider: If the company providing the PaaS
service fails to meet agreed-upon service levels, performance, security,
and availability may be at risk, and moving the application may be
Real World: Windows Azure as a PaaS
• Microsoft .NET has driven the development of many
dynamic web solutions and web services.
• Windows Azure is a PaaS running within Microsoft data
• Users pay only for the scalable processor resources that
• SQL Azure provides a cloud-based database solution for
applications running within Windows Azure.
Windows Azure Continued
• Windows Azure goes beyond .NET and includes
support for Java, PHP, and Ruby. Developers can
build and deploy their solutions to Azure using an
IDE such as Visual Studio or Eclipse.
• Developers can interface to SQL Azure using much
of the same code they would use to access a local
Windows Azure Continued…
• Jamsa, K. A. (2013). Cloud computing: SaaS, PaaS, IaaS,
virtualization, business models, mobile, security and more.
Burlington, MA: Jones & Bartlett Learning.
School of Computer & Information Sciences
ITS-532 Cloud Computing
Chapter 4 – Infrastructure as a Service (IaaS)
Define and describe IaaS and identify IaaS solution providers.
Define and describe colocation.
Define and describe system and storage redundancy.
Define and describe cloud-based network-attached storage (NAS)
devices and identify solution providers.
• Define and describe load balancing and identify cloud-based
• Describe the pros and cons of IaaS solutions.
An IaaS provider makes all of the computing hardware resources available, and the
customers, in turn, are responsible for installing and managing the systems, which
they can normally do, for the most part, over the Internet.
What Data Centers Must Provide
• Access to high-speed and redundant Internet service
• Sufficient air conditioning to eliminate the heat generated by
servers and disk storage devices
• Conditioned power with the potential for uninterrupted power
supply in the short term and long term through the use of on-site
diesel powered generators
• Fire suppression systems
• Administrative staffing to support hardware, networks, and
Bottom Line: Data Centers are Expensive
Co-located Data Centers
• To reduce the risk of a single point of failure, companies
often create a duplicate data center at a remote location.
• Should one of the data centers fail, the other can
immediately take over operations.
• Unfortunately, the second data center will increase the
company’s costs—essentially doubling them—because there
are duplicate servers, storage devices, network equipment,
Internet access, and staffing.
Co-located Data Center
What Co-located Systems Accomplish
• Makes the company less susceptible to fire, acts of God, and terrorism
• Improves performance through a distributed workload
• Makes the company less susceptible to downtime due to power loss from a blackout
• IaaS solutions allow smaller companies to eliminate the need for their own on-site
IaaS Solutions May Support Many Different
• Across the web, sites experience a wide range of
network traffic requirements.
• Sites such as Google, Yahoo!, Amazon, and
Microsoft experience millions of user hits per day.
To handle such web requests, the sites use a
technique known as load balancing, to share the
requests across multiple servers.
Load Balancing Continued
Load balancing uses a server to route traffic to multiple servers which, in turn,
share the workload.
Load Balancing and Replicated Databases
Load balanced systems, for data redundancy, often replicate databases on multiple servers.
Each database, in turn, will send data updates to the other to maintain data synchronization
between the servers.
Cloud-Based Data Replication
Using cloud-based NAS devices and cloud-based databases, companies can
replicate key data within the cloud.
Real World: Rackspace IaaS
• Rackspace has emerged as one of the largest players in the
IaaS market. Rackspace offers a set of solutions that include
cloud hosting, managed hosting (including 24/7 data-center
like management), and hybrid solutions that combine the
cloud and managed services.
• Within minutes, from the Rackspace website an
administrator can select a solution that deploys from 1 to 50
servers. Larger configurations are available.
• Today Rackspace offers cloudbased solutions to hundreds of
thousands of clients. Rackspace houses its data centers at
very large facilities located around the world.
• With respect to the cloud, Rackspace offers pay as you go
scalability, with on-demand storage and load balancing.
Beyond cloud hosting, Rackspace provides solutions for
cloud-based e-mail, Exchange hosting, file sharing, backups,
Network Attached Storage (NAS)
Cloud-based NAS devices present cloud-based storage as mountable devices, which may be
replicated in the cloud to meet a company’s data redundancy needs.
Real World: Nirvanix IaaS
The Nirvanix IaaS provides cloud-based NAS, which is accessible through the
CloudNAS file system.
Advantages of IaaS
Elimination of an expensive and staff-intensive data center
Ease of hardware scalability
Reduced hardware cost
On-demand, pay as you go scalability
Reduction of IT staff
Suitability for ad hoc test environments
Allows complete system administration and management
IaaS Server Types
• Physical server: Actual hardware is allocated for the
customer’s dedicated use.
• Dedicated virtual server: The customer is allocated a
virtual server, which runs on a physical server that may
or may not have other virtual servers.
• Shared virtual server: The customer can access a
virtual server on a device that may be shared with
IaaS Server Types Continued
• Within an IaaS environment, customers can allocate various server
Data Center Technology
Remote Operation and
Hard Disk Arrays
Hot-Swappable Hard Disks
Fast Data Replication Mechanisms
Network Storage Devices
Storage Area Networks (SAN) – dedicated network
Network Attached Storage (NAS) – device connected to network
• Carrier and External Network Interconnection –
Load Balancing and Acceleration
LAN Fabric – High performance and redundant connectivity
SAN Fabric – Used to connect servers to storage devices
NAS Gateways – connection points for NAS storage devices
Jamsa, K. A. (2013). Cloud computing: SaaS, PaaS, IaaS, virtualization, business models, mobile, security
and more. Burlington, MA: Jones & Bartlett Learning.
Erl, T., Mahmood, Z., & Puttini, R. (2014). Cloud computing: concepts, technology, & architecture. Upper
Saddle River, NJ: Prentice Hall.
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